Answer: All the above options are correct about the characteristics of Lumbriculus variegatus.
Explanation:
Lumbriculus variegatus also called the black worm belongs to the phylum Annelida and is used by biologists to illustrate:
-blood vessel pulsations,
-swimming reflex,
-peristaltic crawling behavior,
-giant nerve fiber action potentials.
These studies where carried out on them due to the characteristics they possess. These includes:
-its blood circulates in a closed circulatory system
-Freshwater worm found throughout North America and Europe
-Prefers the shallow habitats found at the edges of ponds, lakes, or marshes
-Feeds on decaying vegetation and microorganisms.
Answer:
Prophase
The replicated chromosomes thicken and become visible as separate chromosomes during prophase stage of mitosis. :)
That would be the nucleus.
The nucleus is the control center of the cell, located in the center of a cell.
The answer is letter d, it is because when a person becomes obese, he or she is likely to intake small amounts of food if he or she wants to maintain his or her weight and if the person does not want to gain weight anymore and than it is more different when gaining weight or when the person was in the point to become obese because he or she has ingested more food to gain weight.